Failed weld on aluminum tube. Why?

[brino]

Franko,

Do you have AC frequency control? If so , what setting did you use?

A picture of the results may be worth 1000 words.

-brino

 

[pontiac428]

I think the key to all aluminum TIG welding is heat control. If you have a big heat sink as a work piece, you've got to get your foot into the pedal a bit, but as soon as (or before) it starts really working, you need to back way off the heat. If one piece is demanding heat and the other is blowing out, you can control the "dwell" of your weave to favor the colder side. Alloy is tricky, makes MIG spool guns really attractive sometimes.

 

[rwm]

I am not saying this is definitely your problem but I have seen a lot of issues with it. Just to make the point. Here is clean, shiny, brushed 6061 sheet all set to weld:



NOT! The shiny part is the polished anodized surface. This will not weld very well at all. In fact if I keep sanding, the material will actually get more gray and dull when I get through the coating. Then it will weld fine.
Maybe this is not an issue for you but hopefully it will help someone else reading this.
Robert

 

[AGCB97]

It is possible my arc distance was too long. I remember the arc wandering.

I would start with a sharp electrode, pencil shape. If you have trouble with it not staying that sharp (like with thick 1/4" or more) then a more blunt angle but still sharp will last longer. A round or contaminated electrode will make the arc wander all over the place. Also use the shortest arc you can muster and closest to 90 degrees as posible.
Aaron

 

[Franko]

I think the key to all aluminum TIG welding is heat control. If you have a big heat sink as a work piece, you've got to get your foot into the pedal a bit, but as soon as (or before) it starts really working, you need to back way off the heat. If one piece is demanding heat and the other is blowing out, you can control the "dwell" of your weave to favor the colder side. Alloy is tricky, makes MIG spool guns really attractive sometimes.

I did have to get my foot into the peddle to get the thick side hot enough to shine. Then the rod would ball up and not flow into it.
(No, I didn't leave the rod in the heat while heating. Once the base metal started to glimmer, I would start dabbing, just like it ususlly works on successful welds.)

I actually did drag out the spool gun. I was able to make it work a little, but the welds were too ugly for prime time on a client project.
I was able to make a few decent welds, but the ones I messed up were terrible. The parts I was making had several pieces and one screw up would mean to scrap the whole thing, cut new pieces and start over.

I would start with a sharp electrode, pencil shape. If you have trouble with it not staying that sharp (like with thick 1/4" or more) then a more blunt angle but still sharp will last longer. A round or contaminated electrode will make the arc wander all over the place. Also use the shortest arc you can muster and closest to 90 degrees as posible.
Aaron

I've gotten pretty good at sharpening my electrodes, being the beginner that I am, I tend to spoil them often. I have a wheel on one of my griders that is used for nothing but tungsten electrodes.

Brino, I took pics but they don't show much. I'll see if I can find them. It was last year. Mostly I tried to weld over the mistakes and attempted to fill holes so many times that the original problem got covered up, especially when I tried tested with the spool gun.

 

[f350ca]

I was welding the lower unit on an outboard one time. The arc didn't sound right and I was having a devil of a time getting a smooth weld. Nothing a flap disk wouldn't fix but was a heck of a fight. Finished up, went to turn the welder off and noticed it was on DC from the last steel I'd welded. Opps

Greg

 

[Franko]

Here are test beads I made on flat surface to get my heat right.
On the top left with TIG, not perfect, but about as good as I can do. If I could have done that on the seam, I would have been satisfied with them.
The two on the bottom right were done with the spool gun.

But, In the middle you see what happened when I tried to TIG the joint.



Inside corner welds were not beautiful but ok enough given my skill level.

 

[rwm]

My guess on that joint is not enough heat? It looks like the filler is just piling up and not melting into a large enough puddle. Little penetration. That weld at the top is awesome!
Robert

 

[Franko]

My guess on that joint is not enough heat? It looks like the filler is just piling up and not melting into a large enough puddle. Little penetration. That weld at the top is awesome!
Robert

I did both welds the same. Yet, one is good and the other sucks. It drove me crazy.
Once I had enough heat to start dabbing the rod, it wouldn't join with the part. It just balled up into a glob. More heat and the thin side of the joint would burn out.

 

[erikmannie]

Are you using 4043 filler material?